Ignition and automatic pilot controls for fuel burners



M y 3, 1955 c. K. STROBEL 2,707,517

IGNITION AND AUTOMATIC PILOT CONTROLS FOR FUEL BURNERS Filed April 28.1949 3 Sheets-Sheet l I INVENTOR. CHARL E6 A. 67-30551.

C. K. STROBEL May3 1 Filed April 28. 1949 3 Sheets-Sheet 2 8% m I J A. nn m 0 I @6 m1 1 u Q. 8 e lllll a 4 ue 7 u w n H g N 81 8N. g ln n u C W3w u m m rill" v. w 0 mm 7 98 N2 B m mm W M .1}. e9 r llll 1 g 2 3. 3---r {\kka Mme I:

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TO'ENE Y.

y 3, 1955 c. K. STROBEL 2,707,517

IGNITION AND AUTOMATIC PILOT CONTROLS FOR FUEL BURNERS Filed April 28.1949 I5 Sheets-Sheet I5 INVENTOR.

CH4 e4 5: A. 67120554.

69 7' TOR/V5)? United States Patent IGNITION AND AUTOMATIC PILOTCONTROLS FOR FUEL BURNERS Charles K. Strobel, Pittsburgh, Pa., assignorto Robertshaw-Fulton Controls Company, Greensburg, Pa., a corporation ofDelaware Application April 28, 1949, Serial No. 90,151

2 Claims. (Cl. 158-130) Fuel burners, such as gas ranges and the like,are

usually provided with constant burning pilots, for the top cookingburners and the oven burners. This practice involves a normallyundesired source of heat and increases the expense of operation of theappliance. The present invention seeks to retain the advantages ofsocalled automatic ignition and pilot control which has heretofore beenpossible with such constant burning pilots. At the same time, however,an object of this invention is to eliminate the undesirable featuresattendant upon the use of constant burning pilots.

Accordingly, the invention provides that all burners in a gas range, forexample, can be ignited from a single igniter while retaining theautomatic pilot control to prevent escape of unburned fuel. Theinvention embodies a catalytic igniter with separate flash-tubes leadingtherefrom to both the top and oven pilot burners for selective ignition.Means responsive to a flame at the oven pilot burner are employed tocontrol the how of fuel to the main burner so that the automatic pilotcontrol feature is preserved.

In a preferred embodiment of the invention, a thermally operable valvecontrols the oven burner fuel supply and is retained in open positionduring the existence of the pilot burner fiame. Such a valve may beeither directly operable by the thermally responsive means or may beelectromagnetically operated in response to energy supplied bythermoelectric means exposed to the pilot burner fiame. Both expedientsare disclosed in detail herein in connection with the accompanyingdrawings which show the preferred embodiment by way of example andwherein Fig. l is a schematic view in perspective of a gas burniugapparatus, such as a gas range, having the ignitio and automatic pilotcontrol applied thereto,

Fig. 2 is a somewhat schematic plan view, shown F partly in section, ofthe ignition and automatic pilot control shown in Fig. 1,

Fig. 3 is a perspective enlarged view of a detail of the structuresshown in Figs. 1 and 2,

Fig. 4 is a top plan view of a gas burning apparatus, such as a gasrange, showing a modified form of ignition and automatic pilot control,and

Fig. 5 is a front elevation, partly in section, of the gas burningapparatus shown in Fig. 4.

Referring more particularly to Figs. 1, 2, and 3 of the drawings, theautomatic pilot control and ignition apparatus is shown with a cookingrange having the usual oven burner and a plurality of top burners 12.Ordinarily, four or more top burners 12 are provided in such ranges butonly two such burners are shown for the purpose of clarity inillustration. As is customary in equipment of this nature, the variousburners receive fuel from a manifold 14 connected to a source of fuelsupply. Thus, the top burners 12 are connected to the manifold 14 bypipes 16 and the fuel supply therein is under control of the usualmanually operated gas cocks 17.

The fuel supply to the main burner 19 is under concated within an endcasing 70.

Patented May 3, 1955 trol of a combined main fuel valve and thermostat20 which may be of the type disclosed in Weber Patent No. 2,303,011. Asstructures of this nature are well known, only the essential portionsthereof will be described herein and reference may be had to theaforementioned patent, if desired, for further details. The combinedvalve and thermostat 20 is shown more clearly in Fig. 2 of the drawingsand comprises a main casing 22 within which a tapered valve member orcock 24 is adapted to rotate. The valve member 24- is hollow and isprovided with a port 26 in its side wall adapted to register with aninlet opening 28 formed in the main casing 22. A pipe 29 serves toconnect the inlet 28 with the manifold 14 for supplying fuel to theinterior of the valve member 24 when the latter is in open position.

Rotation of the valve member 24 is effected by the provision of areduced stem 30 which projects from the larger end of the valve member24 into an end casing or cover 32 secured to the main casing 22. A dialor handle 34 is mounted exteriorly of the cover 32 on a tubularprojection 36 which fits closely in the cover 32 and is spaced from thestem 30. The proiection terminates at its inner end within an annularrecess 3 formed in the main casing 22 adjacent the larger end of thevalve member 24. A sleeve 4. 0 is slidably mounted within the projection36 and is provided with an end flange 42 which enters a slot 44 in theinner end of the projection 36 and provides means by which rotation ofthe dial or handle 34 may be imparted to the sleeve 40.

The flange 42 extends radially beyond the projection 36 into engagementwith a slot l6 formed in the cover 32 opposite the annular recess 38;the arrangement serving as will hereinafter be apparent to preventrotation of the valve or handle 34 until axial movement thereof relativeto the valve member 24 has occurred sufficient to move the sleeve 4%)from a retracted position and release the flange 42 into the recess 38.

The end of the sleeve 40 opposite the flange 42 is provided with aplurality of oppositely disposed tongues 48 which project therefrom intocomplemental slots (not shown) formed in the outer surface of a collar50 secured to the end of the valve stem 30. That portion of the valvestem 39 which is located within the sleeve 40 is preferably reduced indiameter forming a shoulder 52 against which one end of the coil spring54 abuts. The opposite end of the spring 54 abuts a plurality ofprojections 56 formed on the sleeve 40 and located intermediate the endsthereof and serves to bias the sleeve 40 to its retracted position.

The valve stem 30 is provided with an operating shaft 613 connected by apin and slot connection 62 to an eX- tension 61 which projects throughthe main casing 22. The opposite end of the extension 61 carries areciprocable valve member 64 cooperable with an annular valve seat 66formed in the casing 22. A projection 68 on the valve member 64 hasthreaded engagement with a nut 62 lo- The nut 69 is anchored to the endcasing 70 in such manner as to permit relative axial movement whilepreventing relative rotation therebetween. Due to the connectionsdescribed, it is apparent that rotation of the dial 34 will not onlyrotate the main valve member 24 but will also position the valve 3 tuner74. As will hereinafter be explained, the pilot burner 74 may bedispensed with if desired.

Thermostatic means for operating the valve member 64 include a diaphragmelement 80 positioned within the end casing 'ill in operative engagementwith the projection 68 and having the usual capillary tube 82 and bulbelement 8d associated therewith. The bulb element 84 may be located inthe oven or other chamber being heated by the main burner 10. When thebulb member 84 rc sponds to the temperature indicated on the dial 3+5,then the diaphragm element will be sufficiently expanded to seat thevalve member 64 on its seat 66 against the bias of the coil spring 86which is operative between the valve member 6 and the end of the mainvalve member 24.

The flow of fuel in the pipe 13 to the main burner 16 is also under thecontrol of a thermomagnetic control device designated generally by thereference numeral 38. This thermomagnetic control device 88 isinterposed in the main fuel pipe it; in proximity of the top burners 12between the combined main fuel valve and thermostat 2t) and the ovenburner 16". The control device 38 comprises a casing 96 having an inletconnection 92 extending through the side wall thereof adjacent one endand communicating with an axial main fuel chamber 94 therein. The mainfuel chamber 94 is provided with a partition 96 having an axial opening98 to which fuel may flow from the inlet 92 to an outlet 11H) formed inthe wall of the casing 9 at the opposite end of the chamber 94. Theinlet 92 and outlet 19!) serve as connections for opposite ends of thefuel pipe 18 as will be apparent.

- 98 is controlled by safety valve member is movable into and out ofengagement with a valve seat formed on the side of the partition )6adjacent the inlet opening 92. The valve member 102 is secured to avalve stem Hi4 which extends through the opcni 9t; and has slidableengagement with a closure disc 6 which seats on the opposite side of thepartition as. The purpose of the closure disc 166 is to interrupt theflow of fuel through the passage d8 when the valve member 102 is movedout of engagement with its seat during the resetting operation to bedescribed hereinafter.

The closure disc ms is reduced opposite its seating area to slide withinan annular projection or housing 108 on the bottom of the chamber 94. Acoil spring 110 is carried by the reduced end of the closure disc 106and is operative between the housing 168 and an abutment 152 formed onthe reduced end. it should be observed that when a force is applied tothe abutment 112 to move the closure disc Hi5 into engagement with itsseat, the coil spring 11% will be compressed. When the force is removed,the bias of the spring 110 will serve to return the closure disc 36 toits open position relative to the seat. However, a yieldable connectionis also provided between the closure disc 105 and the valve member 162to permit relative movement thercbetween and this connection forms anoverride mechanism which includes a coil spring 114 housed within anaxial recess projecting from the closure disc 196 into the reduced endthereof and being operative between the bottom of the recess and the endof the valve stem 104.

The end of the casing 90 adjacent the inlet 92 is provided with aclosure cap 116 having a magnet housing 113 closely engaging the innerwall thereof. The closure cap 116 at its outer end embodies a threadedterminal connection 126. The magnet housing 118 supports a horseshoemagnet 122 which is provided with the usual winding 124 having one endgrounded on the closure cap 118 and the opposite end secured to theterminal connection 126. The valve stem 104 projects into the magnethousing 118 and the electromagnetic device is completed by the provisionof an armature 126 which is carried by the valve stem 104 forcooperation with the pole faces of the magnet 122.

It should be noted that the armature 126 is normally spaced from themagnet 122 a less distance than the closure disc 1% is spaced from itsscat on the partition 96. Thus, after the armature 126 is in attractedposition against the pole faces of the magnet 122, the override spring114 permits further movement of the closure disc 1% relative to thevalve stem ill-l. When the valve member 102 is fully disengaged from itsseat, then the armature 126 is in attracted position relative to thepole faces of the magnet 122. The valve member 102 is biased to its seatand the armature 126 to its released position by the provision of a coilspring 123 operative between the valve member 102 and the bottom of themagnet housing 118.

The control device 88 also includes means to control the flow of fuel toa flash pilot burner .136 and an auxiliary pilot burner 132. The flashpilot burner 13') is located in the oven compartment adjacent the mainburner 10 while the auxiliary pilot burner 132 is located adjacent thetop burners 12. Both pilot burners 139, 132 are supplied with fuel bythe pipe 134 extending from the control device the auxiliary pilotburner 132 being conveniently connected to the pipe 134 by a branch pipe136. This fuel is under control of the thermomagnetic control device 88by connection of one end of a pipe 138 to an inlet opening 140 extendingthrough the wall of the casing and having its opposite end connected tothe pipe 78. The inlet opening communicates with an auxiliary fuelchamber formed axially of the casing 98 and separated from the main fuelchamber 94 therein by the housing 103. The bottom wall of the chamber142 is apertured to provide passage for fuel from the inlet 14% to anoutlet 144 formed in the wall of the casing 90 on the opposite side ofthe bottom wall and adapted for connection to the fuel pipe 134.

Passage of fuel from the inlet 140 to the outlet 144 is controlled by anauxiliary valve member M6 which is movable into and out of engagementwith the apertured bottom Wall of the chamber 142 by operation of avalve stem 34-3 which is secured to the valve member 146 and extends oneither side thereof. One end of the valve stem 148 is located in thechamber 3.42 and terminates adjacent the abutment 112 with a sealingdiaphragm 143 interposed therebetween. The auxiliary valve member 146 isbiased into engagement with the apertured bottom wall of the chamber 142by a coil spring 150 carried on the opposite end of the stem 142 andwhich is operative between the bottom wall and a collar 151 carried onthe valve stem 143. This opposite end of the valve stem 148 terminatesbeyond the collar thereon for operative engagement with a second sealingdiaphragm 152. A reset stem 154 extends from the opposite side of thediaphragm 152 through the bottom wall of the casing 90 and is providedwith a button 156 exterior of the casing 90 and by means of which thereset stem 354 may be rcciprocatcd.

The electromagnet, comprising the winding 124 and horseshoe magnet 122,is adapted to be energized by current generated from a thermocouple 158which is connected by suitable leads to the winding 124 at the terminalconnection 120. The thermocouple 158 is located so that the hot junctionthereof will be heated by a flame from a thermocouple heating burner 169which receives a supply of fuel from the pipe 134 which also suppliesfuel to the flash pilot burner 13%. it will be apparent that thethermocouple heating burner 160 and the portion of the pipe 134 beyondthe branch pipe 136 could be dispensed with if the ignition pilot burner74 is arranged to heal. the thermocouple 158 and also ignite the mainburner it) and the burner 139 is connected into the supply pipe 78.

As previously indicated, this invention is more particularly directed tothe provision of a catalytic igniler for the burners of the apparatus sothat a constant burning top pilot burner may be dispensed with.Accordingly. a catalytic igniter 161 is supported in a housing 163 andpreferably spaced an equal distance from each of the top burners 12. Anyof the various WBll-hl'lOV/il forms of catalytic igniters may be usedfor the purpose disclosed herein and the material of which the igniteris made forms no part of the present invention. As is well-known, smallpellets, wires, coils or other forms of catalytic material will glow andignite spontaneously when immersed in a steam of gaseous fuel. It ispreferred that the igniter 161 of this disclosure be a cold typecatalyst although other forms are not considered beyond the scope ofthis disclosure.

A flash tube 162 extends between the auxiliary pilot burner 132 and thecatalytic igniter 161 to effect ignition of the pilot burner 132. Aseparate flash tube 165 is provided from the igniter housing 163 to eachof the top burners 12. And elongated flash tube 164 is provided betweenthe auxiliary pilot burner 13-2 and the flash pilot burner 130 which isremote therefrom. In addition, a branch flash tube 166 extends from theflash tube 164 adjacent the flash pilot burner 130 to the thermocoupleheating burner 160. It will be understood that if the burner 168 isdispensed with then the flash tubes 164 and 166 would be arranged toignite the ignition pilot The control device 88 is provided with abracket 168 extending toward the top pilot burners 12 and forming asupport for the auxiliary pilot burner 132. The bracket 168 is providedwith a support 170 upon which a pair of pivoted members 172, 174 arerotatably and separately carried. The pivoted members 172, 174constitute a latch and have interengaging means thereon for rotating onefrom the other. Thus, the member 172 is provided with a projection 176which is adapted to operably engage a complemental projection 1'78carried on the member 174. The member 174 is provided with a slotted end186 opposite the projection 178 thereon and being oflset from thelongitudinal axis.

Extending between the slotted end 180 and the reset button 156 is atiming device comprising a bimetal element 182 which is retained inposition on the reset button 156 by the provision of a transverse slot184 disposed transversely of the longitudinal axis or" the reset stem154. Pivotal movement of the member 174 is restricted by its alternativeengagement with oppositely disposed shoulders 185 formed on the supportmember 17%). As indicated in the drawing, when the reset button 156 isunoperated the birnetal element 182 occupies a position at an angle tothe axis of the reset stem 154. In this position the birnetal element182 is offset from the auxiliary pilot burner 132 which projects throughthe bracket 168 substantially midway between the control device 88 andthe support 170.

Manually operable safety means for moving the bimetal element 182 andlatching member 174 into substantial alignment with the axis of thereset stem 154 are provided. It will be apparent that in such positionthe birnetal element 182 will be subject to the heat of the flame of theauxiliary pilot burner 132. Moreover, in this position the reset button156 will be forced inwardly relative to control device 88 to effect theresetting operation. The manually operable means include connectingmeans between the dial of handle 34 and the pivoted member 172 and takesthe form of a connecting rod 186 supported at one end in an aperturedbracket 188 carried by the pivoted member 172 and providing sufficientclearance for rotation of the member 172 during axial movement of theconnecting rod 186. An ad justing element for the connecting rod 186takes the form of a nut 1% threadedly engaging the end of the rod 186which projects through the bracket 188 and having a bearing thereon forthis purpose.

The opposite end of the connecting rod 186 is pivotally mounted on athird pivoted member 192. The pivoted member 192 is rotatable on abracket 194 projecting from the cover 32 and serves with the pivotedmember 172 to support the connecting rod 186 in substantially parallelarrangement with the control device 88 and the combined valve andthermostatic mechanism 20. A tension spring 196 extends between one endof the third pivoted member 122 and a lug 198 formed on the connectingrod 186 for the purpose of returning the pivoted member 192 to normalposition after operation of the resetting device. It will be apparentthat the spring 196 would not be essential if suflicient bias force maybe obtained from the pivoted members 172, 174 and the birnetal element182 to effect the desired result.

As shown more clearly in Fig. 3, the bracket 194 also supports aslidable key element 280 having an enlarged end 202 engageable with thefree end of the pivoted member 192 and having its opposite endengageable with an operating member or pin 284 projecting from the dialor handle 34. The pin 204 is located on the dial 34 in such positionthat the described engagement will occur when the shut-off cock or valvemember 24 is in its full closed position. Thus, upon axial movement ofthe dial 34 to free the flange 42 from the slot 46 as described herein,which motion is an essential preliminary to rotary motion of the dial34, the slidable element 200 will be moved axially relative to thebracket 194. In order that return movement of the dial 34, while heldinwardly to the initial position shown, will not be interfered with bythe slidable member 200, a pivoted tooth member 206 is provided on theslidable member 200 for engagement by the pin 204. The arrangement issuch that the tooth member 266 will be rotated by the pin 204 as thedial 34 is returned to the 011 position. A flat spring 208 may besecured at one end to the slidable member 200 and have its opposite endengaging the tooth member 206 to return the latter to initial positionwhen the pin 204 no longer exerts a torque thereon.

In the operation of the device disclosed in Figs. 1, 2 and 3, any one ofthe top burners 12 may be placed in operation by merely turning theappropriate gas cock 17 to its open position. The resulting flow of fuelfrom a top burner 12 will enter the associated flash tube and impinge onthe igniter 161. This fuel becomes ignited and the flame travels backthrough the flash tube and ignites the top burner 12. The operation isprecisely the same as if a constant burning pilot were used in place ofthe igniter 161.

The oven burner 10 may be ignited in a simple manner and it may beassumed that the parts are in the position shown in the drawing. Thedial or handle 34 is then pushed inwardly to release the flange 42 fromthe slot 46 preparatory to rotating the dial 34 to a desired temperaturesetting. The initial axial movement of the dial 34 causes the pin 204and the slidable member 288 to move inwardly also and the slidablemember 208 thereupon rotates the pivoted member 192 in a clockwisedirection. The connecting rod 186 is thus pulled to the right as viewedin the drawing and the interengagement of the pivoted members 172, 174causes rotation of the latter in a counterclockwise direction on thesupport 170. The end of the birnetal element 182 which is engaged withthe pivoted member 174 is thus caused to move in a clockwise directionwhereupon the birnetal element 182 assumes the broken line positionshown in Fig. 2 of the drawings.

The rotation of the birnetal element 182 to the broken line positioncauses the reset button 156 and stem 154 to be forced inwardly and to bemaintained in such position during such time as the birnetal element 182remains unheated. The diaphragm 152 and the auxiliary valve stem 148move to the left to open the auxiliary valve member 146. Such movementof the auxiliary valve stem 14% is suflicient to overcome the bias ofthe spring 11% and move the closure disc 166 against its seat on thepartition 96. The valve member 1&2 is moved away from its seat on theopposite side of the partition 9-5 while the armature 126 is moved intoengagement wtih the pole faces of the magnet 122. it should be notedthat immediately prior to engagement of the closure disc 196 with itsseat, that the armature 126 has been moved into ongagement with the polefaces of the magnet 122, but the closure disc 196 can thereafter bemoved into engagement with its seat due to the provision of the overridespring 11- between these elements.

While the description of the various movements which occur upon inwardmovement of the dial or handle 34 may appear lengthy, it will beapparent that only a momentary lapse of time has occurred prior torotative movement of the dial 34 which now is conducted. In other Words,the inward pushing action and subsequent rotation applied to the dial 34are part of a single manual operation which is continuous. Assuming thatthe dial or handle 34 is now rotated to a desired temperature setting,then the port 26 in the shut-off cock or valve member 24 becomesregistered with the inlet opening 28 and fuel is supplied by way of theinlet pipe 29 from the manifold 14 to the interior of the valve member24. Moreover, due to the threaded engagement of the thermostatic valvemember 6 with the nut 69, this valve member is now disengaged from itsseat 66 a predetermined distance corresponding to the selectedtemperature setting on the dial 3+3. Fuel is thus permitted to flowthrough the outlet 72 and pipe 18 to inlet 92 of the control device 83,through the pipe '78 to the i nition pilot burner 74 and also by way ofbranch pipe 1.38 to the control device 88.

As the auxiliary valve member 146 is now disengaged from its seat, thefuel from the branch pipe 133 passes by way of inlet 1 4i) and outlet144 to the pipes 136 and 134. The auxiliary pilot burner 132, the flashpilot burner 130 and the thermocouple heating burner 16% are nowsupplied with fuel. pilot burner 132 travels through the flash tube 162to the catalytic igniter 161 where it is ignited. The liame then travelsback through the flash tube 162 and ignites the auxiliary pilot burner132. The flash pilot burner 130 and the thermocouple heating burner 160are ignited in similar fashion from the auxiliary pilot burner 132through the elongated flash tube 164. The ignition pilot burner "i ialso becomes ignited from the thermocouple heating burner 16%. It willbe observed, however, that no fuel can flow to the main burner 19at-this time due to the engagement of the closure disc 3W6 with its seatand the consequent shutting off of flow of fuel between the inlet 92 andthe outlet 1% of the control device 83.

After a predetermined tlme-deiay during which the bimetal element 182becomes sufficiently heated by the flame from the auxiliary pilot burner132, the element warps and trips the latch comprising pivoted members174- and 172. As the pivoted member 174 is rotated in a clockwisedirection when tripped, the bimetal element 132 is rotated in acounterclockwise direction about the slotted end 18-. in the resetbutton 156 as a pivot. The bimetal element 182 is thus moved out of thepath of a flame from the auxiliary pilot burner 132 to its initial coldposition and simultaneously the force upon the reset button 156 isreleased. The connecting rod 186 is moved to the left, partly under biasof the spring 196 so that the pivoted member 192 and slidable element 2%resume their initial positions shown in the drawing. it will be notedthat the pin 264 has been rotated with the handle or dial 34 out ofoperative engagement with the tooth member 206 so that resumption of theinitial position of the slidable element Zilt) is not interfered with.However, the dial 3 3 is still occupying an inward position and willmaintain such position until the flange 42 on the sleeve 49 can againenter the slot 46. Such entry of The fuel from the auxiliary 8 theflange 42 occurs when the dial 3*; is returned to the initial offposition shown in the drawing and is not effective at this time.

The system has now assumed its steady-state operating condition. Theretraction of the reset stem 154 has caused the auxiliary valve member146 to become engaged with its seat to prevent the flow of fuel from theinlet M0 to the outlet 14-4 so that the flow of fuel through the pipes134 and 136 to the flash pilot burner thermocouple heating burner 160and time for heating the bimetal element 182 sufficiently to cause it towarp is made long enough so that the thermocouple I 3 can becomesufficiently heated by the flame from the thermocouple heating burner65) to gen current for energizing the electromagnet 122,

124 before the auxiliary valve member 146 is moved to .losed position.As the armature 126 is now held in attracted P01 lil3i1 against the polefaces of the magnet 122, t.c valve member 302. remains open while theclosure disc 1% becomes disengaged from its seat under the bias of thecoil spring 110. Flow of fuel from the inlet 92 and the outlet 190 tothe main burner is now permitted. This burner is ignited by the flame atthe ignition pilot burner 74 or, where the latter is dispensed with, bythe flame at the thermocouple heating burner loll.

if at any time during the operation of the apparatus, the thermocoupleE58 ceases to be heated by the flame :rorn the ignition pilot burner 74or, the main burner 1'3 where the ignition pilot burner is dispensedwith, then the armature 26 will be released from the pole faces of themagnet 153.2 causing the valve member 102 to become engaged with itsseat and prevent flow of fuel to the main burner 15). The dial or handle34 may be operated in a counterclockwise direction to its original 017position upon termination of the oven burner operation. During thisreturn movement of he dial 34 the pin 234 will engage and rotate thetoothed member 2'36 so that the return movement is not interfered with.

Cross reference is made to my copending application, Serial No. 790,204filed December 6, 1947, now Patent No. 2,628,677.

It is considered within the scope of this disclosure to provide theauxiliary pilot burner 13?. with an individual catalytic igniter. insuch arrangement, the auxiliary pilot burner 132 would be provided witha second port for the purpose of ignition from the individual catalyticignitcr and the flash tube 162 would be dispensed with. Such anarrangement would have the desirable feature that the oven catalyticigniter would be subjected to the Flame and combustion products onlyduring the relatively short oven starting period. A further modificationof the arrangement hereinbefore disclosed is shown in Figs. 4 and 5 towhich reference will now be had.

Referring now more particularly to Figs. 4 and 5, a common form of rodand tube thermostat 210 has been substituted for the thermomagnetic typeof control previously disclosed. in such event it is apparent that noconnection is necessary between the oven thermostat 2? and the automaticpilot control due to the absence or any necessity for a resettingoperation. Accordingly, the rod and tube thermostat 219, constitutingthe automatic pilot control of this embodiment, is provided with theusual valve member (not shown) for controlling flow of fuel in the pipe18 leading to the main burner The rod and tube element 212 of the thmostat extends toward the main burner 1' for ex.osure to the flame froma pilot burner 214 which located to ignite the main burner 16. The pilotburner 23.4 is supplied with fuel through a bypass connection 216 fromthe oven thermostat 20 so that, as is customary in such devices, theflow of fuel 9 to the pilot burner 214 is not cut ofl when the oventhermostatic valve operates to shut off the main burner supply.

Ignition of the pilot burner 214 is effected by an elongated flash tube218 which extends from the catalytic igniter 161 to adjacent the pilotburner 214. As in the previous embodiment, the catalytic igniter 161 issupported in a housing 163 intermediate the four top burners 12 of thegas range. Also as in the previously described embodiment, the four topburners 12 are provided with separate flash tubes 165 leading from thehousing 163 and effective for causing ignition from the catalyticigniter 161.

In the operation of the device shown in Figs. 4 and 5, the turning on ofa gas cock 17 will cause a gas-air mixture to travel through the flashtube 165 associated with the related top burner 12. Such combustiblemixture is ignited by the catalytic igniter 161 and the flame willtravel back through the tube 165 and ignite the top burner 12.

When the oven thermostat 20 is turned to a desired temperature setting,then a gas-air mixture from the manifold 14 is admitted to the main fuelpipe 18 and also to the by-pass connection 216. As the rod and tubethermostat 210 is interposed in the main fuel pipe 18 and 1 is yetunheated, then no fuel can flow to the main burner 10. The fuel in theby-pass connection 216 enters the flash tube 218 and is conveyed to thecatalytic igniter 161. The resulting flame travels back through the tube218 and ignites the fuel at the pilot burner 214. The flame from thepilot burner 214 serves to heat the rod and tube element 212 and causesthe valve member of the rod and tube thermostat 210 to open and admitfuel to the main burner 10. As the pilot burner 214 can then ignite thefuel at the main burner 10 the system is placed in steady stateoperation.

It will be apparent that in both embodiments of the invention manychanges may be made in the details of construction and arrangement ofparts without departing from the scope of the invention so that thisdescription and accompanying drawings are intended by way ofillustration only and are not to be construed in a limiting sense.

I claim:

1. An ignition and automatic pilot control for fluid fuel burners havinga main burner and a pair of pilot burners comprising a catalytic igniteradapted to respond to a flowing fuel-air mixture for producing a flameat the pilot burners, a control valve member having open and closedpositions for controlling the supply of fuel to the main burner,electromagnetic means operatively associated with said control valvemember for holding the same in said open position when energized,thermoelectric means adapted to be responsive to the heat of the flameat one of said pilot burners for energizing said electromagnetic means,and resetting means operative for positioning said valve member in saidopen position and including thermal timing means adapted to beresponsive to the heat of the flame at the other pilot burner forreturning said resetting means to inoperative position upon completionof said resetting operation.

2. An ignition and automatic pilot control for gas ranges having topburners, a main oven burner and a pair of pilot burners, comprising acatalytic igniter located adjacent the top burners, flash tubesextending between said igniter and the top burners, fuel supply meansfor said burners, a combined thermostatic regulator and main controlvalve device for controlling said fuel supply to I; the main burner,thermally responsive means operably associated with said regualtor andresponsive to oven temperatures for regulating said fuel supply to themain burner in accordance therewith, a bypass connection from saiddevice to one of the pilot burners, an oven flash tube for conveying acombustible mixture from said one pilot burner to adjacent said igniterand producing a flame at said one pilot burner, 21 control valve memberhaving open and closed positions for controlling the fuel supply to themain burner, electromagnetic means operatively associated With saidcontrol valve member for holding the same in said open position whenenergized, thermoelectric means adapted to be responsive to the heat ofsaid flame at the one said pilot burner for energizing saidelectromagnetic means, a flash tube extending between said igniter andthe other said pilot burner, and resetting means operatively associatedwith said device and being operative for positioning said control valvemember in open position, said last means including thermal timing meansadapted to be responsive to the heat of the flame at the other pilotburner for returning said resetting means to inoperative position uponcompletion of said resetting operation.

References Cited in the file of this patent UNITED STATES PATENTS623,572 Simonini Apr. 25, 1899 1,148,409 Roessler July 27, 19151,173,851 Owen Feb. 29, 1916 2,063,834 Bast et al. Dec. 8, 19362,078,576 Laghetto Apr. 27, 1937 2,098,192 Matthews Nov. 2, 19372,113,064 Voice Apr. 5, 1933 2,138,925 Kahn -1 Dec. 6, 1938 2,360,607Kauffman et al. Oct. 17, 1944 2,407,729 Taylor Sept. 17, 1946 2,487,752Cohn Nov. 8, 1949 FOREIGN PATENTS 443,240 Great Britain Feb. 24, 1936

